1. Field of the Invention
The invention relates to an electrical field device for use in industrial control, with a housing, with at least one input, at least one output, and with an electronic circuit which has a microcontroller, a memory and a circuit board. In addition, the invention relates to an expansion module for insertion into an electrical field device, with a housing and with an electronic circuit which has a circuit board.
2. Description of Related Art
Electrical field devices are used in the field of automation for control of systems and machinery in different versions. The heart of the automation is the control which communicates with the individual sensors and actuators which monitor, control and adjust the respective process. For smooth communications between the process and the control, signal matching is often necessary, for which corresponding electrical devices are used which, as a result of their arrangement on the field site, are called field devices. Functionally, these field devices can also in general be called signal converters, the signal converters providing, for example, for signal matching of digital, analog, serial or current and voltage signals between the field side and the control side. The electrical field devices, which can also be called interface modules, are generally used for potential separation between the various signal forms and voltage levels of the signals meeting one another. Therefore, electrical field devices can also be used to separate, amplify, or convert individual signals.
Within the framework of this invention, electrical field devices are defined not only as the above described interface modules or signal converters, but especially relay interfaces in the form of electromechanical load relays or safety relays and optical coupler modules and modular converters for measurement and control engineering, such as, for example, temperature and frequency converters.
If these electrical field devices are connected to a higher-order control via a bus line, configuration of the field devices can take place directly via the bus by means of the control. However, often, it happens that the electrical field devices are used as so-called “stand-alone devices”, i.e., the field devices either do not have a bus connection or are not connected to a bus. Then, configuration of these field devices must take place directly on the device itself.
For simple field devices which have only limited functionality and thus also only a limited number of parameters to be set, configuration of the field devices often takes place by means of rotary coding switches, potentiometers or DIP switches. Electrical field devices with higher complexity often have an operating part with a keyboard and a display for setting and displaying the individual parameters. Due to the generally only limited available space for the keyboard and the display, usually only two or three keys are available for input of the individual parameters, so that complete configuration of the field device is very tedious.
Due to the increasing functionality of electrical field devices, configuration of field devices is also becoming more and more complex, so that control and configuration using operating elements mounted directly on the field device is very difficult. Continually advancing miniaturization leads, moreover, to the fact that, among practicable and ergonomic aspects, it is more and more rarely possible to implement the operating interface directly on the field device. Therefore, in practice, for electrical field devices with medium or high complexity, configuration generally takes place by means of operating software, for which the field devices must be connected to a computer or a laptop.
Additional problems occur in case of a fault or service, since then, either the parameters must be tediously read out from the defective field device by means of the display, or they must be taken from system documentation and transmitted into a new field device. Transmission of data by means of operating software does reduce the parameterization cost, but requires use of a computer and generally the presence of the correspondingly trained personnel.